SBIR Phase II: MEMS Resonant Nanobalance Dew Point Meters

这个小企业创新研究（SBIR）二期项目旨在开发一种基于微机电系统（MEMS）的湿度（露点）测量仪器。微量水分测量需要在各种工业部门，包括天然气生产和分销，半导体制造，纯气体供应，航空航天和石化加工。商业上可用的湿度传感器要么非常昂贵，要么缺乏许多现有应用所需的精度，长期稳定性和响应性。该方法的创新之处在于利用了带有冷却元件的微机电谐振天平。该仪器将使用高精度的冷冻表面技术在谐振天平表面沉积一层水分来测量露点，从而将冷冻表面测量技术的准确性与MEMS实现的小尺寸，低功耗和可负担性相结合。MEMS谐振天平能够检测到几飞克的沉积水分。因此，只有非常少量的气体需要在短时间内冷冻（即低功率/电池操作）以沉积足够的水来指示露点。测量技术的自调零能力消除了频繁维护和校准的需要。该项目的广泛影响/商业潜力包括在过去几十年中没有重大发展的湿度测量技术方面的重大飞跃。所提出的新型露点提供了更高的准确性、响应性、稳定性和鲁棒性，目前在相同的价格范围内是不可用的。天然气中水分的测量是一个具有重大国家意义的重要直接市场。在寒冷的气候条件下，天然气管道中过量的水会使管道冻结关闭，在确定并清除冰点之前，管道将无法使用。此外，由于水分含量的变化以及完全缺乏合适和负担得起的测量设备，湿气被用作天然气行业的定价标准，导致定价误差高达1.74%。拟议的电池或太阳能传感器将允许无人值守操作和数据传输能力，并将安装在天然气井口以及配电网络的不同点上，这些地方对这些类型的测量有很高的需求。

This Small Business Innovation Research (SBIR) Phase II project aims to develop a micro-electro-mechanical system (MEMS)-based moisture (dew point) measurement instrument. Trace moisture measurements are needed in a variety of industrial sectors including natural gas production and distribution, semiconductor manufacturing, pure gas supply, aerospace, and petrochemical processing. Commercially-available moisture sensors are either very expensive, or alternatively lack the required accuracy, long-term stability, and responsiveness for many existing applications. The innovative aspect of the proposed approach is the utilization of micro-electro-mechanical resonant balances coupled with a cooling element. The instrument will measure dew point using the highly accurate chilled surface technique to deposit a layer of moisture on the surface of the resonant balances, hence combining the accuracy of the chilled surface measurement technique the with small size, low power consumption and affordability enabled by MEMS. The MEMS resonant balances are capable of detecting as little as a few femto-grams of deposited moisture. Therefore, only a very small amount of gas needs to be chilled for a short period of time (i.e. low power/battery operation) to deposit sufficient water to indicate the dew point. The self-zeroing capability of the measurement technique eliminates the need for frequent maintenance and calibration.The broader impact/commercial potential of this project includes a significant leap forward in the moisture measurement technologies that have experienced no major development over the past several decades. The proposed new class of dew pointers offers higher accuracy, responsiveness, stability, and robustness currently unavailable at the same price range. An important immediate market with great national significance is the measurement of moisture in natural gas. In cold climates excess water in the gas pipeline can freeze the pipe shut, rendering the pipeline useless until the frozen point can be identified and cleared. Furthermore, due to the variability of the moisture content and the complete lack of suitable and affordable measurement equipment, wet gas is being used as the pricing standard in the natural gas industry, leading to pricing errors of up to 1.74%. The proposed battery- or solar-powered sensors will permit unattended operation and data transmission capability and will be installed at the natural gas wellheads as well as different points along the distribution network where these types of measurements are in high demand.